There have been many proposed ways of synthesizing undeca-1,3,5-triene [see, for example, patent FR 74 19580; patent AS 68 01077; patent application EP 203 615; F. Naef et al., Helvetica Chimica Acta 1975, 58, 1016; V. Ratovelomanana et al.; Bull. Soc. Chim. Fr. 1987, 174; Recherches 1967, 16, 5; W. Boland et al., Helv. Chim. Acta 1987, 70, 1025; E. Block et al., J. Amer. Chem. Soc. 1986, 108, 4568] ever since its discovery [see: Chretien-Bessiere et al., Bull. Soc. Chim. Fr. 1967, 97]. Amongst the methods proposed, there are some which have found an industrial application and undeca-1,3,5-triene is presently commercialized under several tradenames. Since it is characterized by the presence of three ethylenic double bonds in its molecule, undeca-1,3,5-triene can take several isomeric forms, the respective proportions of which in the final product determine its olfactive quality. We have been able to establish that none of the described prior art methods can, at once, satisfy the economic, safety and environmental requirements and provide an irreproachable quality product, of better quality than that of the product currently available on the market.
The process of the present invention has the advantage of providing undeca-1,3,5-triene in the form of a mixture of isomers whose content in the undeca-1,3E,5Z-triene isomer is preponderant. It is precisely this isomer which best develops the most characteristic odor properties; its presence in the mixture thus improves the character of the latter.